Here's another amazing enzyme video produced by Sarah and Alyssa from the SL Biology class.
Wednesday, September 23, 2009
Tuesday, September 15, 2009
How do enzymes work?
Some students from the Gr 11 SL Biology class made an animated video of how enzymes work to catalyse chemical reactions. They also show in the video how inhibitors can stop enzymes from working. Have a look below it's been posted on Youtube..
Monday, April 13, 2009
2009 Gr 11 Biology Field Expedition
In the week before the holidays the Gr 11 Biology students traveled to Tioman Island to study various ecosystems in order to compliment the current topic, Ecology and Evolution.
On the five day course students studied in depth the ecology of coral reefs, primary and secondary rainforests and both coastal and estuarine mangroves. Each student completed two major pieces of work while away; one involved collating data through various techniques to compare primary and secondary rainforests, the other was a personal project. The personal project requires them to develop a research question regarding a particular ecological aspect of Tioman Island. They then spend an afternoon in the field gather data relating to their question. This year we had personal projects relating to the claw waving behviour of fiddler crabs, the angle of bending of coconut trees, the attraction of insects to different coloured paper flowers and the distribution of different species of sea cucumbers. Our students worke hard and the time spent was very worthwhile.
On the five day course students studied in depth the ecology of coral reefs, primary and secondary rainforests and both coastal and estuarine mangroves. Each student completed two major pieces of work while away; one involved collating data through various techniques to compare primary and secondary rainforests, the other was a personal project. The personal project requires them to develop a research question regarding a particular ecological aspect of Tioman Island. They then spend an afternoon in the field gather data relating to their question. This year we had personal projects relating to the claw waving behviour of fiddler crabs, the angle of bending of coconut trees, the attraction of insects to different coloured paper flowers and the distribution of different species of sea cucumbers. Our students worke hard and the time spent was very worthwhile.
Wednesday, February 4, 2009
Why are plants green?
Chlorophyll is the pigment responsible for making plants green and it is found in the chloroplasts of plant cells. It is responsible for capturing light energy from the Sun and using it to drive photosynthesis in the chloroplast.
The Science Department recently purchased a spectrophotometer which allows students to expose samples of solutions to many different wavelengths of light and then measure how much of the light a solution absorbs.
In order to utilise the spectrophotometer, the Gr 12 Higher Level Biology class recently asked the question: "Does the chlorophyll from different plants show similar absorbance spectra?"
To answer this question they extracted the chlorophyll from diffent green leaves and exposed the chlorophyll solution to different wavelengths of light using the spectrophotometer.
The results of their experiment are shown in the graph below. Each line represents the absorbance spectrum of one type of chlorophyll. As it shows, the chlorophyll samples all showed peaks of absorbance at wavelengths in the blue and red areas of the visible spectrum. The difference in height of the peaks is due to the different concentrations of chlorophyll in each sample. The low level of absorbance in the green area explains why plants are green - they absorb red and blue light but reflect green light!
Tuesday, October 14, 2008
2008 Gr 11 Biology Field Trip
In September the Gr 11 Biology classes completed a week long field course on Tioman Island. Here they had the opportunity to extend their study of ecology by applying their knowledge to field work on the island. The students studied the coral reef, mangrove, rocky shore and rainforest ecosystems in depth. They completed two major pieces of research which will form part of their Internal Assessment portfolio of work for their IB Diploma.
It was a fantastic week as the photos below show........
It was a fantastic week as the photos below show........
Wednesday, August 27, 2008
Grade 8 WASTE PLASTICS PROJECT
Our class, Ms Carter’s Gr 8 Science class, did a “Waste Plastics Project”. For a week, we had to collect plastics that we were going to throw away and bring them to class. The day we chose to do our tally was on Wednesday, 20/08/2008.
We left all our plastics in a corner of the science lab, and they piled up into a heap as big as a mountain!
Items collected included plastic bottles, containers, snack wrappers, plastic bags and so on. With the help of our fellow classmates, we separated all the collected items
into different categories, and placed them around the lab accordingly.
By the end of the categorizing, there were massive piles of plastic items spread across the desks. Who would have guessed that just twenty families had already amassed such a large amount of plastic waste in just a week?! Imagine just how much more plastic would have been wasted across Singapore!!
TABLE TO SHOW WASTE PLASTICS COLLECTED:
As you can see from the results of our “WASTE PLASTICS PROJECT”, the amount of plastic that is wasted is huge and should be seen as a GREAT cause for concern!
Here are a few ways YOU can help cut down on the amount of waste plastic without drastically altering your lifestyle:
1) When you get takeaway from hawker centres, the vendor will usually pack your food in plastic containers. The next time you get food from the hawker centre, you should bring along the plastic containers you received the last time and ask the vendors to put your food in those you brought instead of giving you more.
2) The next time you go grocery shopping, bring along an eco-friendly cloth bag or a rucksack to put your groceries in, instead of using plastic bags.
3) If you get drinks in plastic bottles, you should reuse those plastic
bottles as your drinking bottles or throw them in the recycling bin.
But the easiest way to cut down on buying drinks packed in plastic bottles is simply not to buy them! Besides, those drinks are nothing but sugar and completely unnecessary anyway!
4) DO NOT USE PLASTIC UTENSILS. Use steel utensils instead.
Now, you have no excuse to waste plastic ever again!
Did you know…??
* Singapore’s landfill sites are located at Ulu Pandan, Pulau Semakau, Senoko, Tuas and Tuas South.
* One of Singapore’s landfill sites, Tuas South, is one of the largest in the world.
Plastic cannot biodegrade. Plastic waste thus takes up a lot of landfill space.
* Pulau Semakau (Singapore’s newest landfill site) is expected to last until 2030 – only slightly over twenty years from now. However, if the amount of waste produced in Singapore continues to rise, the lifespan of the Pulau Semakau landfill might be shorter than expected.
We left all our plastics in a corner of the science lab, and they piled up into a heap as big as a mountain!
Items collected included plastic bottles, containers, snack wrappers, plastic bags and so on. With the help of our fellow classmates, we separated all the collected items
into different categories, and placed them around the lab accordingly.
By the end of the categorizing, there were massive piles of plastic items spread across the desks. Who would have guessed that just twenty families had already amassed such a large amount of plastic waste in just a week?! Imagine just how much more plastic would have been wasted across Singapore!!
TABLE TO SHOW WASTE PLASTICS COLLECTED:
As you can see from the results of our “WASTE PLASTICS PROJECT”, the amount of plastic that is wasted is huge and should be seen as a GREAT cause for concern!
Here are a few ways YOU can help cut down on the amount of waste plastic without drastically altering your lifestyle:
1) When you get takeaway from hawker centres, the vendor will usually pack your food in plastic containers. The next time you get food from the hawker centre, you should bring along the plastic containers you received the last time and ask the vendors to put your food in those you brought instead of giving you more.
2) The next time you go grocery shopping, bring along an eco-friendly cloth bag or a rucksack to put your groceries in, instead of using plastic bags.
3) If you get drinks in plastic bottles, you should reuse those plastic
bottles as your drinking bottles or throw them in the recycling bin.
But the easiest way to cut down on buying drinks packed in plastic bottles is simply not to buy them! Besides, those drinks are nothing but sugar and completely unnecessary anyway!
4) DO NOT USE PLASTIC UTENSILS. Use steel utensils instead.
Now, you have no excuse to waste plastic ever again!
Did you know…??
* Singapore’s landfill sites are located at Ulu Pandan, Pulau Semakau, Senoko, Tuas and Tuas South.
* One of Singapore’s landfill sites, Tuas South, is one of the largest in the world.
Plastic cannot biodegrade. Plastic waste thus takes up a lot of landfill space.
* Pulau Semakau (Singapore’s newest landfill site) is expected to last until 2030 – only slightly over twenty years from now. However, if the amount of waste produced in Singapore continues to rise, the lifespan of the Pulau Semakau landfill might be shorter than expected.
Monday, July 28, 2008
Chlorophyll and Starch in Leaves
On the 24/7/08, Tuesday. Our Grade 10 FIB class, 10RRa learnt a new topic for biology lesson, photosynthesis. To allow us to have a better understanding of how photosynthesis occurs, Dr Hjorth engaged us in an experiment which requires us to test for starch in a piece of leaf.
Our class was then divided into several groups. Whereby we then obtained leaves from various plants and begin on our experiment.
Our group consisted of Yvette, Nicole and Sunshine. Dr Hjorth gave us a piece of leaf that looked distinctively different from the ordinary green leaves. The colour of the leaf was as of such, from the centre, pink, pale yellow, to the edges which are green. According to our knowledge, only the green parts of the leaves contain starch. Yet now we have a leaf with 3 shades, would the coloured parts possibly test positive to starch?
Step 1: First we had to place the leaf in boiling water for a minute to soften it.
Step 2: Once that is done, we place the leaf into a new test-tube with ethanol. Stand the test-tube in a beaker of hot water for around 10 minutes.
Step 3: Wash the leaf in cold water
Step 4: Spread the leaf flat on the Petri dish and cover it with iodine solution. If the leaf turns blue-black, it means starch is present.
After conducting the required steps, we obtained the following results:
As you can see, the places which were green turned blue-black, indicating starch was present where chlorophyll was. The pale coloured parts of the leaf stayed the colour they were, indicating starch was absent. So we can conlude that chlorophyll is involved in photosynthesis producing starch. The reason why a substance like starch is used for storage in plants is because it is insoluble, and does not cause problems like osmosis, unlike glucose.
Our class was then divided into several groups. Whereby we then obtained leaves from various plants and begin on our experiment.
Our group consisted of Yvette, Nicole and Sunshine. Dr Hjorth gave us a piece of leaf that looked distinctively different from the ordinary green leaves. The colour of the leaf was as of such, from the centre, pink, pale yellow, to the edges which are green. According to our knowledge, only the green parts of the leaves contain starch. Yet now we have a leaf with 3 shades, would the coloured parts possibly test positive to starch?
Step 1: First we had to place the leaf in boiling water for a minute to soften it.
Step 2: Once that is done, we place the leaf into a new test-tube with ethanol. Stand the test-tube in a beaker of hot water for around 10 minutes.
Step 3: Wash the leaf in cold water
Step 4: Spread the leaf flat on the Petri dish and cover it with iodine solution. If the leaf turns blue-black, it means starch is present.
After conducting the required steps, we obtained the following results:
As you can see, the places which were green turned blue-black, indicating starch was present where chlorophyll was. The pale coloured parts of the leaf stayed the colour they were, indicating starch was absent. So we can conlude that chlorophyll is involved in photosynthesis producing starch. The reason why a substance like starch is used for storage in plants is because it is insoluble, and does not cause problems like osmosis, unlike glucose.
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